A telephone typically comprises a plurality of input keys, a handset for transmitting and receiving voice information, and a cradle for holding the handset. A “hook switch” located proximate the cradle changes its electrical state when the handset is placed into or removed from the cradle, providing an indication to the telephone network as to whether the telephone is “on hook” (i.e., in a standby mode) or “off-hook” (i.e., in an active or in-use mode). Equipment that utilizes a telephone network for non-voice communications, such as facsimile machines and computers, provide equivalent on- and off-hook electrical signals that enable the telephone network to determine whether or not the telephone line connected to the equipment is in use.
The public and private telephone networks to which the telephone is connected provide real-time information paths between two or more parties. The public system is generally referred to as the Public Switched Telephone Network (“PSTN”), while private systems, such as a telephone network within a business, are generally referred to as a Private Branch Exchange (“PBX”). Traditionally, these public and private information paths have taken the form of voice connections, originally through hardwired analog circuitry but later through an increasingly broad range of technologies such as radio transmission, digital signal encoding, and fiber optics. Over time, these information paths have also begun to be used for non-voice applications such as fax and data transmission and reception.
Modern telephones and telephone networks provide a variety of calling features, such as call waiting, call hold, call pick-up, call transfer, conference calls, call forwarding, call redirection, automatic call-back, and speed dialing. These features are typically manually enabled or disabled by a user, who enters a series or “string” of command inputs via the input keys, sometimes beginning with a “flash” input. A flash input is executed by momentarily depressing the telephone's hook switch to place the phone on-hook, then releasing the hook switch. Many telephones have a separate flash key to accomplish the flashing function. An example command string is effective to disable the call-waiting feature by inputting “flash,” “*,” “7” and “0.” Equipment that utilizes a telephone network may likewise be adapted to generate command string inputs under the control of a user.
Many electronic printing devices utilize telephone networks to send and receive non-voice data. One such device is an all-in-one (“AIO”) device. An AIO device is a multifunction device that may function, for example, as a printer, scanner and copier. Such AIO devices may also function as a facsimile or “fax” machine when connected to a conventional telephone line. AIO devices generally cost less, take up less space, and use less energy than separate printers, scanners, copiers and fax machines. Further, AIO devices are often able to multitask between functions, increasing the user's productivity. Since an AIO device provides a plurality of functions in a single unit, connecting the AIO device to other equipment, such as computers, is greatly simplified as compared to wiring separate, single-function units. AIO devices are often networked to allow multiple users to access a single device.
There are times when it is desirable to enable or disable certain calling features when a non-voice communication device is connected to a telephone line. For example, a telephone network's call waiting feature may preferably be disabled during the transmission or reception of a fax message because the call waiting tone that notifies a user of an incoming call may interfere with the transmission or reception of the fax. Thus, there exists a need for a receiving device connected to a telephone line that is able to perform a set of predetermined tasks, such as enabling, disabling, initiating and halting a calling feature, in response to some predetermined event, such as an incoming call having predetermined characteristics.